It is often desirable in the manufacturing industries to utilize an adjustable support for supporting a workpiece or the like. Hydraulic supports, typically an oil filled hydraulic cylinder can be used as such an adjustable support. The height of the adjustable support cylinder is locked by trapping a volume of hydraulic fluid inside the hydraulic cylinder and the height can be adjusted by adding or removing fluid from the hydraulic cylinder. An example of a workholding device uses adjustable length hydraulic cylinders.
It would be desirable to provide improvements in such hydraulic supports, so that the support could be relatively compact and self-contained, and adjustable in length without exterior valving, pumps, reservoirs or the like.